In this study, semivariance was used to quantitatively measure the spatial heterogeneity for the egg population of cotton bollworm during a growing season. The typical characteristic parameters of theoretical semivari...In this study, semivariance was used to quantitatively measure the spatial heterogeneity for the egg population of cotton bollworm during a growing season. The typical characteristic parameters of theoretical semivariance models against lag distances were applied to measure components of spatial heterogeneity： trend, range, spatial dependence, and the strength of spatial dependence. Then, kriging interpolation was used to evaluate the population risk of cotton bollworm exceeding economic thresholds. From early June through early September, the population densities were sampled 10 times in the study field. Results showed that the spatial patterns were related to population density. For its low-density population, the spatially heterogeneous trends were usually of spherical shapes; but for highdensity ones, the trends shifted to Gaussian shapes. The spatial dependence appeared at varied distances ranging from 52 meters to 936 meters, and the spatial dependence was in the range of 0.39-288.60, which changed with population densities. While having high heterogeneity, the strength of spatial dependence became much stronger. Results of population risk analysis showed that there was a high risk during its early stages, especially in mid-June. In August, population risk was so low that it did not need to be controlled.展开更多
Environmental fluctuations are a pervasive natural phenomenon that typically favor diverse maternal investment strategies.Organisms across various evolutionary lineages have acquired the ability to enter the dormancy ...Environmental fluctuations are a pervasive natural phenomenon that typically favor diverse maternal investment strategies.Organisms across various evolutionary lineages have acquired the ability to enter the dormancy state to tolerate conditions that are unsuitable for normal life activities.In cyclical parthenogenesis,sexual reproduction is generally linked with dormancy,thereby enhancing the long-term fitness of populations through positive feedback mechanisms.This study evaluates the impact of environmental variability on offspring population dynamics through sexual reproduction in the rotifer Brachionus calyciflorus.We found that mictic females(sexual females)exposed to low-predictability environments produced resting eggs with a sporadic hatching pattern,reduced hatching rate,and smaller sizes of resting egg,embryo,and stem females,while increasing variations in fertilization among individuals to maximize population fitness.Variations in population growth could be manifested in enhanced reproductive capacity 2–3 d post-hatching,along with differences in fecundity among individuals.This suggests that dormant eggs from unstable environments may prioritize offspring survival and adjust to increased fertilization among individuals.This adaptive strategy enables rotifer populations to rapidly adjust to environmental changes,thus avoiding extinction and thriving in diverse habitats.Our systematic study enhances the understanding of how environmental stability affects long-term population fitness in cyclical parthenogens.展开更多
With the development of metabolic engineering,increasing requirements for efficient microbial biosynthesis call for establishment of multi-strain co-culture system.Dynamic regulation of population ratios is crucial fo...With the development of metabolic engineering,increasing requirements for efficient microbial biosynthesis call for establishment of multi-strain co-culture system.Dynamic regulation of population ratios is crucial for optimizing bioproduction performance.Optogenetic systems with high universality and flexibility have the potential to realize dynamic control of population proportion.In this study,we utilized an optimized chromatic acclimation sensor/regulator(CcaS/R)system and a blue light-activated YF1-FixJ-PhlF system as induction modules.A pair of orthogonal quorum sensing systems and a toxin-antitoxin system were employed as communication module and effector module,respectively.By integrating these modules,we developed a dual light-controlled co-culture system that enables dynamic regulation of population ratios.This co-culture system provides a universal toolkit for applications in metabolic engineering and synthetic biology.展开更多
Livestock grazing has been demonstrated to affect the population abundance of small rodents in grasslands,but the causative mechanism of grazing on demographic parameters,particularly the age structure and sex ratio,i...Livestock grazing has been demonstrated to affect the population abundance of small rodents in grasslands,but the causative mechanism of grazing on demographic parameters,particularly the age structure and sex ratio,is rarely investigated.In this study,we examined the effects of sheep grazing on the cohort structure and sex ratio of Brandt’s vole(Lasiopodomys brandtii)in Inner Mongolia of China by using large manipulative experimental enclosures during 2010-2013.Our results indicated that sheep grazing significantly decreased the proportion of the spring-born cohort,but increased the proportion of the summer-born cohort.Grazing increased the proportion of males in both spring and summer cohorts.In addition,we found a negative relation between population density and the proportion of the overwinter cohort.Our results suggest that a shift in the cohort structure and the sex ratio may be an important strategy for small rodents to adapt to changes in food resources resulting from livestock grazing.展开更多
Objective:To examine variation in the frequency of arm damage in different sizes of Acanthasterplanci(A.planci),assess how this damage is inflicted by fish predators,and infer the potential role of predation in popula...Objective:To examine variation in the frequency of arm damage in different sizes of Acanthasterplanci(A.planci),assess how this damage is inflicted by fish predators,and infer the potential role of predation in population regulation.Methods:and arm damage frequency and severity was assessed.Frequency of arm damage was compared between sizes.Feeding behavior of fish predators was also observed in the laboratory.Results:This study demonstrates that sublethal predation by triggerfishes on A.planci result inDiameters of A.planci collected from three sites in the Philippines were measured extensive arm damage.Overall,60%of A.planci sampled across all sites had sublethal injuries.The frequency of individuals with missing or regenerating arms was highest in medium-sized young adults(11-20 cm),which coincides with the phase where A.planci shift from cryptic to exposed daytime feeding.Conclusions:The high incidence of arm damage within intermediate-sized sea stars indicates that predators exercise some level of regulation on A.planci populations at a local scale.Identification and protection of putative predators that target the most vulnerable life history stages of A.planci are essential in developing population control strategies and reverse sustained declines in coral cover.展开更多
文摘In this study, semivariance was used to quantitatively measure the spatial heterogeneity for the egg population of cotton bollworm during a growing season. The typical characteristic parameters of theoretical semivariance models against lag distances were applied to measure components of spatial heterogeneity： trend, range, spatial dependence, and the strength of spatial dependence. Then, kriging interpolation was used to evaluate the population risk of cotton bollworm exceeding economic thresholds. From early June through early September, the population densities were sampled 10 times in the study field. Results showed that the spatial patterns were related to population density. For its low-density population, the spatially heterogeneous trends were usually of spherical shapes; but for highdensity ones, the trends shifted to Gaussian shapes. The spatial dependence appeared at varied distances ranging from 52 meters to 936 meters, and the spatial dependence was in the range of 0.39-288.60, which changed with population densities. While having high heterogeneity, the strength of spatial dependence became much stronger. Results of population risk analysis showed that there was a high risk during its early stages, especially in mid-June. In August, population risk was so low that it did not need to be controlled.
基金Supported by the National Natural Science Foundation of China(No.32071528)。
文摘Environmental fluctuations are a pervasive natural phenomenon that typically favor diverse maternal investment strategies.Organisms across various evolutionary lineages have acquired the ability to enter the dormancy state to tolerate conditions that are unsuitable for normal life activities.In cyclical parthenogenesis,sexual reproduction is generally linked with dormancy,thereby enhancing the long-term fitness of populations through positive feedback mechanisms.This study evaluates the impact of environmental variability on offspring population dynamics through sexual reproduction in the rotifer Brachionus calyciflorus.We found that mictic females(sexual females)exposed to low-predictability environments produced resting eggs with a sporadic hatching pattern,reduced hatching rate,and smaller sizes of resting egg,embryo,and stem females,while increasing variations in fertilization among individuals to maximize population fitness.Variations in population growth could be manifested in enhanced reproductive capacity 2–3 d post-hatching,along with differences in fecundity among individuals.This suggests that dormant eggs from unstable environments may prioritize offspring survival and adjust to increased fertilization among individuals.This adaptive strategy enables rotifer populations to rapidly adjust to environmental changes,thus avoiding extinction and thriving in diverse habitats.Our systematic study enhances the understanding of how environmental stability affects long-term population fitness in cyclical parthenogens.
基金supported by the financial grant from National Natural Science Foundation of China(82071383,82371392)Natural Science Foundation of Shandong Province(Key Project,ZR2020KH007)+5 种基金the"Taishan Scholar Distinguished Expert Program"of Shandong Province(tstp20231257)Natural Science Foundation of Shandong Province(ZR2022QC222)Shandong Province Medical and Health Science and Technology Project(202404070807)Youth Science Foundation of Shandong First Medical University(202201-132)Talent Introduction of Jinan Central Hospital(YJRC2022002)Science and Technology Development Program of Jinan Municipal Health Commission(2024102001).
文摘With the development of metabolic engineering,increasing requirements for efficient microbial biosynthesis call for establishment of multi-strain co-culture system.Dynamic regulation of population ratios is crucial for optimizing bioproduction performance.Optogenetic systems with high universality and flexibility have the potential to realize dynamic control of population proportion.In this study,we utilized an optimized chromatic acclimation sensor/regulator(CcaS/R)system and a blue light-activated YF1-FixJ-PhlF system as induction modules.A pair of orthogonal quorum sensing systems and a toxin-antitoxin system were employed as communication module and effector module,respectively.By integrating these modules,we developed a dual light-controlled co-culture system that enables dynamic regulation of population ratios.This co-culture system provides a universal toolkit for applications in metabolic engineering and synthetic biology.
基金supported by the State Basic Research Program of the Ministry of Science and Technology(2007CB109100)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB11050000).
文摘Livestock grazing has been demonstrated to affect the population abundance of small rodents in grasslands,but the causative mechanism of grazing on demographic parameters,particularly the age structure and sex ratio,is rarely investigated.In this study,we examined the effects of sheep grazing on the cohort structure and sex ratio of Brandt’s vole(Lasiopodomys brandtii)in Inner Mongolia of China by using large manipulative experimental enclosures during 2010-2013.Our results indicated that sheep grazing significantly decreased the proportion of the spring-born cohort,but increased the proportion of the summer-born cohort.Grazing increased the proportion of males in both spring and summer cohorts.In addition,we found a negative relation between population density and the proportion of the overwinter cohort.Our results suggest that a shift in the cohort structure and the sex ratio may be an important strategy for small rodents to adapt to changes in food resources resulting from livestock grazing.
基金Supported by the Department of Sustainability,Environment,Water,Population&Communities-National Environmental Research Program-Tropical Ecosystems Hub.
文摘Objective:To examine variation in the frequency of arm damage in different sizes of Acanthasterplanci(A.planci),assess how this damage is inflicted by fish predators,and infer the potential role of predation in population regulation.Methods:and arm damage frequency and severity was assessed.Frequency of arm damage was compared between sizes.Feeding behavior of fish predators was also observed in the laboratory.Results:This study demonstrates that sublethal predation by triggerfishes on A.planci result inDiameters of A.planci collected from three sites in the Philippines were measured extensive arm damage.Overall,60%of A.planci sampled across all sites had sublethal injuries.The frequency of individuals with missing or regenerating arms was highest in medium-sized young adults(11-20 cm),which coincides with the phase where A.planci shift from cryptic to exposed daytime feeding.Conclusions:The high incidence of arm damage within intermediate-sized sea stars indicates that predators exercise some level of regulation on A.planci populations at a local scale.Identification and protection of putative predators that target the most vulnerable life history stages of A.planci are essential in developing population control strategies and reverse sustained declines in coral cover.
